使用Meteor将没有其方法的JS对象存储在Mongo中

Question

I have a JS object (ES6) like this in a Meteor project:

export class MyClass {
    constructor() {
        this.data: uuid.v4(),   
        this.updated: new Date(),
    }

    action() {
        this.updated = new Date();
    }
}

I am saving it to a MongoDB collection like this:

let id = myDB.insert(new myClass());

Later, I fetch the object by Id:

let persisted = myDB.findOne({ _id: id });

If I run the following, it works and updates the updated property of the object:

persisted.action();

Now, this is rather convenient, and I am tempted to run with it, but it appears to be storing the logic of the action method into MongoDB. This seems inefficient because I will have many saved instances of MyClass all with the same action() method.

Is it standard practice in Meteor to store objects in this manner, or is there some way to conveniently strip the methods away from the object prior to saving it so that only the data and updated properties are stored?

Answer 1

You could consider adding a method to your class that returns a JSON version of your object. Then, you should insert this JSON version to your MongoDB. Also, you should change your constructor to accept arguments, this will be useful when fetching the object from the database.

Add this constructor to MyClass:

constructor(data, updated) {
    this.data = data;
    this.updated = updated;
}

Add the following method to MyClass :

toJSON() {
    return {
        data: this.data,
        updated: this.updated
    }
}

Instantiate the class:

let myObject = new myClass(uuid.v4(), new Date());

Then, call JSON.stringify on myObject :

let myObjectJSON = JSON.stringify(myObject)

Finally, insert myObjectJSON in your MongoDB collection:

let id = myDB.insert(myObjectJSON);

Every time you call JSON.stringify on a object instace from a class that has a method called toJSON , this method will be called.

When you fetch this document from your collection, create a new instace from MyClass passing as arguments to the constructor the fields inside the document.

let persisted = myDB.findOne({ _id: id });
let persistedObject = new myClass(persisted.data, persisted.updated);